The passivation behavior of the P-implanted alloys in a Cl-containing electrolyte as a function of Cr concentration and P implantation has been investigated. At low Cr concentrations (6% Cr), P implantation sufficient to form an amorphous layer degrades the passive behavior of the base alloy and induces pitting, and at high-Cr levels (18%) P has little effect on passivation. However, at intermediate Cr levels (8%, 10%), P implantation significantly improves passivity, with the greatest improvement occurring at 10% Cr. When implanted to ∼25% P, the Fe–1OCr alloy exhibits a decrease in the passive current density by 4 orders of magnitude relative to the unimplanted alloy, and shows current decay characteristics that closely resemble those of the Fe–18Cr alloy.

ZnSe layers have been grown on (100)-oriented Ge substrates by molecular beam epitaxy for the first time. The optimum in-situ Ge substrate preparation technique was found to consist of argon-ion sputtering at room temperature followed by annealing at ∼400°C. This cleaning technique provided Ge surfaces which exhibited (2X2) surface reconstruction as observed by reflection high-energy electron diffraction and which had O and C contamination levels below the detection limit of the Auger electron spectroscopy system. ZnSe layers grown on argon-ion sputtered and annealed (100)Ge substrates using a variety of substrate temperatures and Zn to Se beam pressure ratios were characterized by 4.2 K photoluminescence (PL) measurements. The highest quality layers as judged by PL analysis were grown in the substrate temperature range, 310–350°C, with a Zn to Se beam pressure ratio around unity. ZnSe layers grown under these conditions exhibited a dominant donor-bound exciton peak at 2.7976 eV having a minimum linewidth of ∼1.1 meV.

Dielectric breakdown of gas mixtures can be used to deposit thin films by chemical vapor deposition with appropriate control of flow and pressure conditions to suppress gas-phase nucleation and particle formation. Using a pulsed CO2 laser operating at 10.6 μ where there is no significant resonant absorption in any of the source gases, homogeneous films from several gas-phase precursors have been sucessfully deposited by gas-phase laser pyrolysis. Nickel and molybdenum from the respective carbonyls representing decomposition chemistry and tungsten from the hexafluoride representing reduction chemistry have been demonstrated. In each case the gas precursor is buffered with argon to reduce the partial pressure of the reactants and to induce breakdown. Films have been characterized by Auger electron spectroscopy, x-ray diffraction, transmission electron microscopy, pull tests, and resistivity measurements. The highest quality films have resulted from the nickel depositions. Detailed x-ray diffraction analysis of these films yields a very small domain size consistent with the low temperature of the substrate and the formation of metastable nickel carbide. Transmission electron microscopy supports this analysis.

The 27Al and the 55Mn nuclear magnetic resonance powder pattern lineshapes have been obtained in icosahedral and decagonal (T phase) Al-Mn quasiperiodic crystals, and are compared to that of orthorhombic Al6Mn. The quasiperiodic crystals yield much broader spectra with little resolved structure. The quadrupole and Knight shift parameters for the 55Mn resonance in orthorhombic Al6Mn have been determined as |vQ| = 0.76 MHz,Kax = −2.7 × 10−4, Kiso = + 5 × 10−3. The results imply that Al6Mn and the quasiperiodic crystals have similar electronic and magnetic properties.

Since the definition of quasiperiodicity is intimately connected to the indexing of a Fourier transform, for the case of an icosahedral solid, the step necessary to prove, using diffraction, that an object is quasiperiodic, is described. Various coordinate systems are discussed and reasons are given for choosing one aligned with a set of three orthogonal two-fold axes. Based on this coordinate system, the main crystallographic projections are presented and several analyzed single-crystal electron diffraction patterns are demonstrated. The extinction rules for three of the five icosahedral Bravais quasilattices are compared, and some simple relationships with the six-dimensional cut and projection crystallography are derived. This analysis leads to a simple application for indexing powder diffraction patterns.

The crystallization behavior of an arc-melted, splat-quenched amorphous Ta55–Ir45 alloy was investigated by differential thermal analysis (DTA) and transmission electron microscopy (TEM). The DTA experiments showed that the glass transition temperature (Tg) for this material was 485 °C and that the crystallization temperature (Tx) closely followed at 495 °C. This Tx is much lower than has been previously reported. In-situ TEM annealing experiments, in addition to confirming Tx, illustrated that crystallization proceeds as a two-step process. A fcc phase is the first to crystallize at 500 °C followed by the equilibrium phases, α and σ, and/or the bcc Ta phase near 600°–650 °C. Microhardness measurements were made as part of an initial mechanical properties investigation. Inconsistencies with the work of previous investigators of this system are discussed.

CuCr multilayers, 0.5−1 /um total thickness, on Cu substrates have been laser irradiated. Threshold energy densities for complete alloying with different laser wavelengths and different multilayer structures were determined using Rutherford backscattering. Results are discussed in terms of absorbance of Cu and Cr as a function of laser wavelength, overall chemical composition, and thicknesses of the individual Cu and Cr layers. Also, x-ray diffraction was used to study the microstructure of the CuCr before and after laser irradiation. A method is outlined for unraveling the contributions to peak shift of stacking faults, stresses, and change in'chemical composition. The CuCr alloy produced by the laser irradiation consisted of small, very defective Cu-rich and Cr-rich crystallites. The CuCr layer was subjected to a high tensile stress. The distinct change in preferred orientation of crystallites on laser irradiation indicated a complete melting of the CuCr multilayer. A high tensile strength (> 935 MPa) of the CuCr before and after laser alloying is suggested by the microstructure as observed by x-ray diffraction and sustained by hardness measurements. In the Cu-rich crystals 4.0 at. % Cr was in solid solution, i.e., five times the maximum equilibrium solid solubility.

High electron mobility thin InSb films were prepared on mica substrates by conventional vacuum evaporation of InSb to obtain highly sensitive magnetoresistance (MR) elements. The 0.15–0.5 μm thick InSb films were prepared in the present work. An optimum evaporation programming pattern was obtained. The crystal properties of these InSb films of 0.2–0.3 μm were investigated using a transmission electron microscope. It was shown that films thinner than 0.2 μm were semitransparent and consisted of [111] oriented single-crystal films. The 0.15–0.3 μm thick InSb films are therefore most useful for low-cost MR elements because of their high element resistance, small temperature coefficient of electron mobility, and high sensitivity.

Homogeneous single phase Mg32Al19Zn30 was melt spun to form flakes suitable for TEM examination. The nodular structure gave diffraction patterns with 5.3.2 icosahedral point group symmetry. The formation of the icosahedral phase is rationalized in terms of the Mg(AlZn)49 equilibrium structure. This structure is a Frank-Kasper phase. It has previously been established how such icosahedral order can be anticipated in the Frank-Kasper phases.

A buildup of radiation-induced lattice defects is proposed as the cause for lattice instability that can give rise to a crystalline-to-amorphous transition. An analysis of published experiments on intermetallic compounds suggests that, when amorphization takes place, no microstructural evolution based on the aggregation of like-point defects occurs. This observation leads us to suggest that buildup of a different type of defect, which will destabilize the crystal, should occur. We thus propose that an interstitial and a vacancy may form a complex, giving rise to a relaxed configuration exhibiting a sort of short-range order. Two mechanisms of complex formation are analyzed, one diffusionless (limited by the point defect production rate) and the other temperature dependent. The amorphization kinetics as a function of temperature, dose, and point defect sink strength are studied. Theoretical predictions on the amorphization dose as a function of temperature are made for the equiatomic TiNi alloy and compared with available experimental results.

We report the preparation and properties of higher nitrides of Hf, Zr, and Ti synthesized by dual ion beam deposition. For Hf and Zr, evidence is given for the existence of a metastable nitride phase with composition of approximately Hf3 N4 and Zr3 N4. These two materials are insulating and transparent straw colored, in contrast to the well-known mononitrides, which are shiny, gold colored, and highly conducting. For Ti-N we do not reach as high an N content and do not obtain an insulating, transparent phase. The higher nitrides of Hf and Zr are synthesized under energetic nitrogen ion bombardment (200 e V) of a growing film and do not form in the presence of molecular nitrogen gas alone. Several variations of the ion beam deposition process are used to obtain a wide range of film composition and to study the transition from the mononitride to the higher nitride phase. Transmission electron diffraction shows the structure of Hf3N4 and Zr3N4 to be very close to the Bl (NaCl) structure of the mononitrides, but with a slight rhombohedral distortion. Additional evidence from noble gas incorporation (Ne, Ar, and Xe) supports a model of these higher nitrides as containing a large number of vacancies on the metal atom sites.

The evolution of the implant distribution during ion implantation at elevated temperatures has been theoretically studied using a comprehensive kinetic model. In the model foreign atoms, implanted into both interstitial and substitutional sites of the host lattice, could interact with implantation-induced point defects and with extended sinks such as the bombarded surface. The synergistic effects of preferential sputtering, radiation-enhanced diffusion, and radiation-induced segregation, as well as the influence of nonuniform defect production, were taken into account. The bombarded surface was allowed to move in either direction, − x or + x, depending on ion energy, i.e., on the competition between the rates of ion deposition and sputtering. The moving surface was accounted for by means of a mathematical technique of immobilizing the boundary. The ion implantation process was cast into a system of five coupled partial differential equations, which could be solved numerically using a suitable technique. Sample calculations were performed for two systems: Si+ and Al+ implantations into Ni. It has been known from previous studies that in irradiated Ni, Si atoms segregate in the same direction as the defect fluxes, whereas Al solutes migrate in the opposite direction. Thus the effects of different segregation mechanisms, as well as the influence of target temperature, ion energy, and implantation rate on the evolution of implant concentrations in time and space, could be examined with the present model.

The well-known glass-forming alloy Fe40Ni40P14B6 was surface melted by an electron beam traversing its surface at various velocities in an identical manner for both the crystalline and the amorphous state of the alloy. Cross-sectional optical metallography and numerical heat-flow analysis were used to show that (1) crystallization of the amorphous state does not occur during treatment around or in the regrown layer at the highest processing speeds, a behavior consistent with an extrapolation of isothermal nucleation and growth measurements; (2) initial resolidification of the molten layer is always crystalline when the melt pool contacts underlying crystalline material where nucleation is immediate; and (3) solidification front velocities greater than 5 ± 0. 5 cm/s exceed the maximum kinetic limit for growth of the crystalline phase and amorphous layers are formed, a result consistent with the eutectic nature of the alloy. Inconsistencies with the work of previous investigators of this system are discussed.

A new double-layered stacked LSI fabrication process has been developed for the purpose of realizing short fabrication turn-around time, high fabrication yield, and high integration density. This process, which is named “Elemental Level Vertical Integrated Circuit (ELVIC)” technology, puts two conventionally made LSI chips face to face and bonds them by thermal compression. The process includes, in addition to the conventional LSI fabrication process, vertical interconnection (VI) formation in the upper and lower LSI layers, planarization of both upper and lower layer surfaces, and inter-level connections using pressure and heat. In the experimental version, about 52 000 10X10μm2 Au-on-Ti VIs were connected on a 5×5 mm2 chip. Each pair of mated VIs was measured and had a tensile strength of 4 mg · force. A two-layer, 31-stage inter-CMOS/bulk ring oscillator consisting of p-channel MOSFETs on the upper layer and n-channel MOSFETs on the lower layer has been built. Propagation delay time per stage is 1.86 ns at the supply voltage of 5 V. ELVIC technology can produce a variety of benefits such as high production yield, doubling integration density, latchup-free CMOS LSIs, radiation-damage-free LSIs, multifunction, and complete mixing of bipolar, CMOS, and GaAs technologies.

Powder flakes prepared from 50/um thick melt-spun ribbons of Markomet 1064 (Ni52.5 Mo38 Cr8 B 1.5 wt %) were shock consolidated in the unannealed and annealed condition. The unannealed powder flakes (microhardness 933 kg/mm2) are amorphous while flakes annealed at 900°C for 2 h have a fcc crystal structure, with a microcrystalline grain size of 0.3 μm and microhardness of 800 kg/mm2. The shock-consolidated amorphous powder compact (∼250 kJ/kg shock energy) shows no crystal peaks in an x-ray diffractometer scan. Compacts of annealed powder (400–600 kJ/kg shock energies) contain amorphous material (18%–21%), which was rapidly quenched from the melt formed at interparticle regions during the consolidation process. The microhardness of the amorphous interparticle material is 1100 kg/mm2. Wear properties of the compacts measured in the low velocity friction apparatus (LVFA) pin-on-disk tests show low average friction values (−0.03). The 60 h cumulative wear appears to correlate with the energy of shock compaction rather than the metallic glass content. The Falex ring-on-block test also showed that both the Markomet amorphous compact and the compact containing a mixture of amorphous and microcrystalline phases performed almost equally and wore half as much as the base-line SAE-01 steel-polished sample.

Measurements of pressure-concentration (p-c) isotherms of hydrogen in a wide variety of amorphous Ni—Zr alloys are presented. The measurements are complemented by an analysis of hydrogen sites in computer-generated amorphous clusters. The binding energy of these sites has been calculated using an effective medium theory. Filling these sites randomly in order of decreasing binding energy with a nearest-neighbor exclusion leads to a chemical potential in agreement with what is found from the (p-c) isotherms. In the pressure range required in a hydrogen-storage device (1–10 atm) the hydrogen occupies interstitial sites surrounded by 3Zr, 1Ni atoms or 2Zr, 2Ni atoms.

In an ultrahigh vacuum (UHV) environment, thin poly crystalline Ni films have been deposited on a Zr (112) single-crystal surface. In contrast to the case of poly crystalline Ni and Zr films, formation of amorphous Ni—Zr is not observed upon annealing at 300 °C for 11.5 h. The possible presence of an oxide or an amorphous phase diffusion barrier is ruled out and therefore the lack of a reaction must be due to a reaction barrier at the single-crystal Zr/ Ni interface. Either ion mixing of the interface with 400 keV, 5 × 1015 Xe+ /cm2, or deposition of a poly crystalline Zr layer in between the Zr single crystal and the Ni overlayer can overcome this reaction barrier. These results indicate that grain boundaries in polycrystalline Zr play an important role in amorphous Ni—Zr formation by a solid-state reaction.

Electron-beam-induced changes in the structure of partially amorphous CdS surfaces have been observed directly by atomic-resolution electron microscopy. A sequence of atomic rearrangements leading to nucleation and growth of cubic CdS and hexagonal Cd has been documented. Inelastic electron collisions lead to crystallization of overlying amorphous CdS material whereas electron-stimulated desorption of S from the underlying CdS crystal results in precipitation of Cd crystallites at the crystalline/amorphous interface. From 100 to 500 keV the events are almost energy-independent.

Compound samples of NiAl3 as well as Ni23Al77 multilayered samples have been irradiated by either Xe or Ne ions to doses of 2 × 1015 Xe ions/cm2 and 1.3 × 106 Ne ions/cm2 at temperatures of 100 K, 300 K, and 373 K. In the case of compound irradiation, NiAl3 stability appears to be determined by regrowth kinetics and increased with lighter irradiating ion mass and higher irradiation temperature. The formation of NiAl3 by ion mixing Ni/Al multilayers was not affected by irradiating ion mass and appears to be limited by nucleation.

Among chemically bonded ceramics (i.e., those not utilizing thermally activated diffusion for bonding) the French synthetic opal gilsonite provides an excellent existence theorem. By using optical, scanning, and electron microscopy techniques and x-ray, chemical, and differential thermal analyses, it is shown for the first time that the synthetic opal is composed of two separate phases: noncrystalline silica and crystalline (tetragonal) zirconia balls. The zirconia balls with sizes ranging from 7-50 nm appear to be present in an extraordinary regular “lattice” in the void spaces of the silica “balls” of mean size 200 nm. A comparison of the fracture toughness, Kic, data for the gilsonite and natural opal shows that the former is significantly tougher than the latter. The KIC values for gilsonite fall between those of the Corning 0337 Glass Ceramic and Wesgo Al-500 alumina, showing that surprisingly tough ceramics can be made near room temperature by resorting to chemical bonding.